What happened
In the Linux kernel, the following vulnerability has been resolved: powerpc/xive: propagate IPI init errors to prevent use-after-free When xive_init_ipis() fails (e.g. irq_domain_alloc_irqs() fails), the error path frees the global xive_ipis array. However, xive_smp_probe() previously ignored this failure and proceeded to call xive_setup_cpu_ipi(), which dereferences the already-freed xive_ipis pointer -- a use-after-free. Now that xive_smp_probe() returns int (previous patch), propagate the error from xive_init_ipis() and xive_setup_cpu_ipi() through xive_smp_probe(). Check the return value in both pnv_smp_probe() and pSeries_smp_probe() so that IPI setup is aborted cleanly on failure, avoiding the use-after-free.
Affected versions
Linux: 243e25112d06b348f087a6f7aba4bbc288285bdd through before c554a8d376d5aea1b237ed6bef6f9fbfc550e67f (git); 243e25112d06b348f087a6f7aba4bbc288285bdd through before 411a3c016e7a95f5fa105a0587e07d0647a77727 (git); 4.12 Fixed: See vendor advisory.
Why it matters
Review the vendor advisory and exposure of the affected product to determine operational impact.
Detection & mitigation
- Apply vendor-provided updates or mitigations.
- Review affected product exposure and access logs.
Public PoC references
No public PoC reference has passed the current publication threshold.